[PATCH] D47343: [MCJIT] Call JIT notifiers only after code sections are ready.

[Andres Freund via Phabricator via llvm-commits]

anarazel created this revision.
anarazel added a reviewer: reames.
Herald added a subscriber: llvm-commits.

Extracted from https://reviews.llvm.org/D44892

Previously JIT notifiers were called before relocations were
performed (leading to ominious looking function calls of "0" being
shown in debugger / profiles), and before memory marked
executable (confusing some profilers).

Move notifications to finalizeLoadedModules().


Repository:
  rL LLVM

https://reviews.llvm.org/D47343

Files:
  lib/ExecutionEngine/MCJIT/MCJIT.cpp
  lib/ExecutionEngine/MCJIT/MCJIT.h


Index: lib/ExecutionEngine/MCJIT/MCJIT.h
===================================================================
--- lib/ExecutionEngine/MCJIT/MCJIT.h
+++ lib/ExecutionEngine/MCJIT/MCJIT.h
@@ -190,6 +190,8 @@
   SmallVector<std::unique_ptr<MemoryBuffer>, 2> Buffers;
 
   SmallVector<std::unique_ptr<object::ObjectFile>, 2> LoadedObjects;
+  SmallVector<object::ObjectFile*, 2> PendingLoadedObjects;
+  SmallVector<std::unique_ptr<RuntimeDyld::LoadedObjectInfo>, 2> PendingLoadedObjectInfos;
 
   // An optional ObjectCache to be notified of compiled objects and used to
   // perform lookup of pre-compiled code to avoid re-compilation.
Index: lib/ExecutionEngine/MCJIT/MCJIT.cpp
===================================================================
--- lib/ExecutionEngine/MCJIT/MCJIT.cpp
+++ lib/ExecutionEngine/MCJIT/MCJIT.cpp
@@ -220,8 +220,10 @@
   if (Dyld.hasError())
     report_fatal_error(Dyld.getErrorString());
 
-  NotifyObjectEmitted(*LoadedObject.get(), *L);
-
+  // Can't call notifiers yet, as relocations have not yet been
+  // performed, and memory hasn't been marked executable.
+  PendingLoadedObjects.push_back(LoadedObject->get());
+  PendingLoadedObjectInfos.push_back(std::move(L));
   Buffers.push_back(std::move(ObjectToLoad));
   LoadedObjects.push_back(std::move(*LoadedObject));
 
@@ -241,6 +243,16 @@
 
   // Set page permissions.
   MemMgr->finalizeMemory();
+
+  // Notify listeners about loaded objects, now that memory is marked
+  // executable and relocations have been performed.
+  for (size_t i = 0; i < PendingLoadedObjects.size(); i++) {
+    auto &Obj = PendingLoadedObjects[i];
+    auto &Info = PendingLoadedObjectInfos[i];
+    NotifyObjectEmitted(*Obj, *Info);
+  }
+  PendingLoadedObjects.clear();
+  PendingLoadedObjectInfos.clear();
 }
 
 // FIXME: Rename this.


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